Gearing.



W. O. KENNINGTON.

GEARING.

,APPLLCATIQN FILED FEB. 6, 1915.-

1,197,744. Patented Sept. 12, 1916.

UNITED STATES PATENT OFFICE.

wI'LLrAM o. KENN'INGTON, or ANDERSON, INDIANA, ASSIGNOR, BY MESNEASSIGN- MEN TS, T0 ECLIPSE MACHINE COMPANY, OF

or 1\TEW YORK.

ELMIRA, NEW YORK, A CORPORATION GEARING.

Specification of Letters Patent. Patented Sept. 12, 1916.

Application filed February 6, 1915. Serial N 0. 6,559.

To all whom it may concern Be it known that I, W'ILLIAM O. IQEN:

NINGTON, a subject of the King of England, and a resident-of Anderson,in the county of Madison and State of Indiana, have invented a new anduseful Improvement in Gearing, of which the following is aspecification.

My invention relates to gearing wherein a gear is caused to slide intoor out of mesh with another gear by traveling along a screw threaded orsimilar shaft.

The particular purpose of my invention is to prevent the gear on thethreaded shaft from rebounding into engagement with the other gear afterit has been thrown out of mesh therewith, and a further purpose is toreduce the blows on the ends of the teeth at the time of meshing. I thusreduce the wear and destruction of the teeth. 1

I have made the invention with reference to the gearing connectingelectric starting motors to internal combustion engines but attachedparts, shown partly in section, and

turned in the opposite direction to Fig. 1. Fig. 3 is a view of theright hand end of Fig. 2, but with the shaft also shown. Fig. 4 is asection of the pinion alone along the line 44: of Fig. 2. Figs.'5 and 6show modified forms of my invention, being sections through the weight,normal to the axis of the shaft 20, (corresponding to a section alongtheline 55 of Fig. 2 looking toward the left).

Referring to' Fig. 1, there is an internal combustion engine, havingcylinders 1, crank case 2, crankshaft 3 and flywheel 4, similar to thoseordinarily used. The flywheel. 4: has teeth on its periphery, so that itcan act as a gear. There is a bracket 6, integral with the crankcase 2,to which is secured the electric starting motor 7. There isa storagebattery 8 and starting switch 9, said motor, battery and switch beingconnected in series by the wires 10, 11 and 12.

- This extension is screw'threaded, with one,

two or more threads, as may be desired. There is a small gear, or pinion21 on the shaft 20, and this (see Fig. 2) is internally threaded, sothat rotation of the pinion relative to its shaft causes the pinion totravel longitudinally along the shaft. Referring again to Fig. 1, therelations of the shafts 3 and 20 are such that when the pinion 21 hasmoved to the right its teeth mesh with those with the flywheel. Theteeth of both gears are preferably chamfered on the ends which engageeach' other when meshing starts. There is, preferably, a spiralcompression spring 22, having its right hand end secured to the shaft20, but its left hand end free to stop the'motion of the pinion. lVhenthe pinion 21 abuts this spring, saidpinion is in mesh with the gear 1.There is a pin 24 projecting radially from the left end of the shaft 20,against which can abut a shoulder, hereinafter described, of the pinion21, and when this occurs, the pinion is far enough to the left for itsteethto be entirely free of those of the gear 4.

There is a weight retainer 25, shownin detail in Figs. 2 and 3, on oneend of the pinion. This is rigidly secured to the pin ion, in the formshown this being done by a very tight fit between the weight retainerand the pinion. Surrounding said weight retainer is an annular weight30. The

weight may rotate on the weight retainer, but there must be a certainamount of friction between these parts as will appear later. There is anannular groove 31 in said weight, adapted to be filled with grease orother suitable material which will cause this free of those of the gear4.

The mechanism is preferably, though not necessarily, arranged so thatthe pinion 1s in engagement when at the inner end of ts motion, that is,when it is in the position nearest the motor, as shown herein. Thisconstruction is advantageous in that the leverage 'efi'ect tending tobend'the shaftor otherwise strain the mechanism during the use thereofis less than if the pinion were operative when at the outer end of itslongitudinal motion. V

The above describedform of the invention operates as follows: Referringto Fig. 1, when the starting device is not in use, the position of thepinion '21 is far to the left, so that the teeth of said pinion and theflywheel 4 are entirely free of each other, this being the normal orinoperative position. To start the engine, the switch 9 is closed,whereby the storage battery 8 starts the electric motor 7, and the shaft20 is thus rotated. "The pinion 21, however, turns but slowly, insteadof acquiring the speed of the shaft. This is due to the inertia of thepinion 21, and that of the weight 30. If the friction between the pinionand the weight is great enough to cause the weight to rotate with thepinion, this weight merely adds its inertia to that of the pinion, butif the pinion turns faster than this weight, the frictional resistancebetween the weight and the pinion still tends to retard the rotation "ofthe pinion. Thus, at this period in the operation of the apparatus, theweight helps to make the rotation of the pinion slow compared with thatof the shaft whether or not there is any relative motion between thepinion and the weight. w

Since the pinion is rotating slower than the shaft-20, the screw and nutrelation between this shaft moves the pinion to the right, and its teethare brought into mesh with those of the gear 4:. After the pinion hasmoved far enough to the right to bring it fully in mesh with the gear.4, the longitudinal motion of the pinion is stopped by theabutment ofthe pinion 21 against the spring 22. After this occurs, the pinion 21 1sobliged to rotate at least as fast as the shaft 20. The motion of thisshaft, acting than the shaft,'and,

through the pinion 21, now causes the flywheel 4: to rotate and theengine is started. By employing the spring 22 instead of a rigid stop,the longitudinal motion of the pinion is stopped gradually, and theengine is started withless shock than if the longipinion were arrestedThis makes the pinion travel to the left, whereby its teeth are umneshedfrom thoseof the flywheel.. The motion of the pinion to the left isstopped by the, abutment of the shoulder 32 against the pin 24 and theprincipaladvantage of this invention is in the manner in which thisstopis made. In

ordinary forms of arrangement, wherein the pinion is not provided with aweight movable relatively thereto, it often occurs that the pinion,after striking the pin, rebounds therefrom and travels far enough towardthe flywheel, resulting in injury to the ends of the teeth, and myinvention prevents this as follows: WVhen the engine is started, thespeed of the pinion 21 is suddenly increased,

-and the inertia of the Weight together with the possibility of relativemotion between the weight and the pinion may prevent this weight fromacquiring as rapid rotation as that acquired at this time by the pinion.As soon as the teeth of the pinion are free from those of the flywheel,so that the speed of the pinion is no longer determined by the speedof'the flywheel, the frictional drag between the weight and the. pinionlowers the speed of rotation of the pinion. The excess of the pinionspeed above the shaft speed is thereby reduced, so that when theshoulder on the .pinion abuts the pin 24, it is moving slowly ,relatvelyto this pin and does not rebound;

Even if the weight should acquire the v speed of the pinion when thepinion is aocelerated by the engine, this weight is still useful inpreventing rebound of the pinion, for when the shoulder -on the pinionabuts the pin 24, the moment of inertia of the I weight causes it tocontinue turning faster should the pinion rebound, the friction betweenthe weight and the pinion would cause the weight to drag the pinion backagainst the pin .24, instead of permitting the motionof rebound tocontinue so far that the teeth of the pinion clash w1th those of theflywheel. Of course, after the engine is started, the motor is stopped,as usual, by opening the switch 9.

A method which has heretofore been used to-prevent the rebound of thepinion from causing clashing of the teeth has been to so arrange theparts that when the pinion has reached the left hand limit of its motionthere is a considerable longitudinal distance between the teeth of thepinion and those of the flywheel, so that the rebound of the pinion willnot be sufficient to cause clashing of the teeth. Compared with myinvention, this possesses two disadvantages: First, it requires a longershaft to provide for this increased clearance. This is particularlyobjectionable in automobiles, where the parts are crowded. Second: Thepinion will frequently stop with less rebound than the maximum reboundthat must be provided for in the clearance and therefore the pinion willhave to travel farther before going into engagement than with myinvention. Now, the farther the pinionhastotravel longitudinally, thefaster the rotation it will acquire before engagement of the teeth. Thisrotation should be kept to as low an amount as possible, because ittends to rub together and injure the ends of the teeth at the instantthat they are just engaging.

In Fig. 5 the friction between the pinion or rather the weight retainerand the weight 30 is augmented by a fiat spring 140, secured by screws141 to the weight retainer,

here.designated 131, said Weight retainer.

being suitably recessed to accommodate this spring. The tendency of" thespring 149 to straighten itself increases the friction existing betweenthe weight 30, and the weight retainer 131.

Fig. 6 shows a form of the invention wherein the weight, here designated230, and not provided with an annular groove can rotate faster than thepinion 21, but not slower. The weight and the weight retainer aremechanically connected by what may be termed a ratchet like connection,since it permits the same character of relative motion as. does aratchet. There is a recess in the inner periphery of the weight, inwhich is a cylindrical roller 240. There is a plunger 241, fitting in ahole in the weight 230 and forced against the roller 240 by a spiralspring 242. The shape of the notch in the weight 230 is such that whenthe weight is rotated, relatively to the pinion 21, in the directionindicated by the arrow, the roller does not cause binding be"- tween theweight and the weight retainer 31, but when an attempt is made to turnthe weight in the opposite direction, the roller moves toward the narrowportion of the notch and grips the weight retainer 31, so as to preventrotation. This mechanism is well known and understood, and is here shownas an example of the various forms of ratchet like connection that maybe employed. In this form of my invention, the weight cannot rotateslower than the pinion, although it may rotate faster, due to the theweight assisted in limiting rotation, and

therefore produced quick meshing, even though there was no motion of theweight relative to the pinion, and it was also shown that even if theweight should acquire the speed of the pinion, when the pinion isaccelerated by the operation of the engine under its own power, that theweight would continue to rotate after the shoulder on the pinion abutsthe pin 24, andthat this continuance of rotation would assist inpreventing or limiting the rebound of the pinion from the pin. This isWhat occurs in the last mentioned form of the invention.

In the foregoing I have described the i more important use of myinvention, but I do not limit it to the specific application shown,since it may be applied to many other types of mechanism besidesstarting motors for internal combustion engines. Neither do I limit myinvention to the specific constructions shown, since, it may beconstructed in a variety of ways without departing from the spirit ofthe invention. For example, the motion wherein translation occurssimultaneously with rotation and which I term a substantially helicalmotion, may be produced by other means than the cooperating internal andexternal screw threads shown. Furth rmore, I do not limit myself togears having their shafts or axes parallel.

I claim as my invention:

1. In a starter for engines, the combination-with a threaded shaft, athreaded pinion thereon, and a gear to be started by the pinion, of aweight carried by the pinion and rotatablerelatively thereto.

2. In a starter for engines, the combina tion with a threaded shaft, athreaded pinion thereon, .and a gear to be started by the pinion, of anannular weight carried by the pinion and rotatable relatively thereto.

3. In a starter for engines, the combination with a threaded shaft, athreaded pinion thereon, and a gear to be started by the pinion, of anannular weight carried by the pinion and rotatable relatively thereto,and

friction means between said weight and pinion.

4. In .a starter for engines, the combination with a threaded shaft, athreaded pinion thereon, and a gear to be started by the pinion, of anannular weight rotatable on said pinion, and a spring friction devicearranged between said weight and pinion.

5. In a starter for engines, the combination with a threaded shaft, athreaded pinion thereon, and a gear to be started by the pinion, of aneccentricweight rigid with the pinion, and an annular weight mounted on5 and rotatable relatively to the pinion.

6. In a starter for engines, the combination with a threaded shaft, a,threaded pinion thereon, and a gear to be started by the pinion, of a.weight carried by the pinion and rotatable relatively thereto, and a 10spring abutment for cushioning the intermeshing of said pinion and gear.

WILLIAM O. KENNINGTON.

Witnesses:

Z. MI SMITH, F. P- MCDERMOTT, Jr.

